How can I activate an actuator if A is false and B is true?
Assumptions
You have two AddObjectActuators?
You activate both randomly?
You want that only one at the time gets activated?
Analysis
It seams you have two independent random results that both decide when a certain object gets created.

Possible solution
How about changing the decisions? One random result decides when an object gets created and a second random result decides what object gets created.
How to decide what object to create?
You have two (or more actuators to activate) so you need a random result that represents one of the possible actuators. The simplest representation is you number them:

Actuator A
Actuator B

This way you can use the random actuator to generate a random number between 1 and you maximum (2) to be placed in a property. With the random actuator you can decide the likelihood what actuator to activate (e.g. you want 50:50 so you use &quot;Int Uniform&quot;

How to decide when to activate the actuator?
You already did that with the random sensor. It acts as &quot;Bool Uniform&quot; which means 50:50 chance.

How to connect both aspects?
This example just show how to randomly generate a random object number:

Now you add the actuators dependent on the previous choice:

You check what actuator to activate either 1 or 2 and activate the actuators. Only one condition can be positive at the same time.
We do this after the random actuator completed (actuator sensor). Otherwise there can be another object after a one frame delay, which looks like it created a second object at the same time.

Another Possible solution
You decide the what as above. You decide the when the same way. The benefit is that you get better control how to generate the wait time.
Now you get two properties:

one with the actuator number (actuatorNumber) and
one with the time to wait (waittime).


The timer property counts upwards so we generate negative wait times. When the wait time gets positive it is time to generate a new actuator number, new wait time and activate one of the actuators.
Interestingly the activation logic is the same as in the above solution. So I do not repeat it here.
I hope it helps
PS: I forgot to mention:
When deciding what to activate you can add &quot;unmapped&quot; numbers. This way it decides to activate nothing (e.g. 0=nothing, 1=Actuator A, 2=Actuator B).